Ion implantation of semiconductor wafers is generally accomplished by supporting a plurality of semiconductor wafers on a disk (or other support element), mounting the disk inside a vacuum chamber, and directing an ion beam at the disk while it is moved with respect to the beam. After implantation is complete, new wafers are substituted. This is conventionally done by manually removing the disk from the chamber and substituting another disk loaded with the new wafers. The time required to perform the interchange subtracts from time available for implantation, thereby lowering the throughput of implanted wafers.